The transport of glucose into muscle is an important control point in the regulation of energy metabolism in muscle and in the maintenance of the blood glucose level. Insulin, contraction, and anoxia accelerate the transport while fatty acid oxidation inhibits it. However, except for the case of insulin, little is known about the mechanisms involved in this regulation. In addition, the glucose transporter has not been purified from muscle, and its kinetics have not been characterized. The objectives of the proposalare to purify the muscle glucose transporter and to study its structure, kinetics, and regulation. The glucose transporter will be purified from skeletal muscle after extraction of membranes with detergent. Immunoaffinity chromatography, using an antibody against the human erythrocyte glucose transporter, may be an important step in the purification. Other procedures (chromatography, gel filtration, density gradient centrifugation) will also be employed in the purification. Transport activity, binding of cytochalasin B, and cross-reactivity with the antibody will be used as assays in the purification. The purified protein will be reconstituted into liposomes to give D-glucose transport activity, and some kinetic features of the protein identified. The amino acid composition of the transporter and its molecular weight in both SDS and monionic detergent will be determined. Possible mechanisms of the regulation, such as CA++, calmodulin, and protein kinases, will be tested using the purified transporter. Furthermore, the transporter will be isolated from red, white, and heart muscle, and the kinetic, structural, and regulatory properties compared. A more complete understanding of the regulation of glucose transport in muscle is relevant to clinical problems such as diabetes, heart disease, and muscle disease, and will provide important information in the general areas of metabolic regulation and the structure and function of transport proteins.